EXPLANATION OF FIGURES 



1 First indication of cleavage. 



2 First furrow; from above. 



3 First furrow, more advanced; from below. 



4 Second cleavage; from above. 



5 Eight-celled stage; from above. 



6 More advanced stage of cleavage; from above. 



7-14 Formation and closure of neural folds; 7, 9, 11, 13, 14, anterior and dorsal 

 views; 8, 10, 12, posterior views. 



15 Two small clutches of eggs, about | natural size. 



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